UDOT celebrates centenary of the electric traffic signal

The Utah Department of Transportation (UDOT) is celebrating the 100th anniversary of the invention of the electric traffic signal by opening a traffic signal history display at its Traffic Operations Center. The display features a replica of the USA’s first traffic signal, which was invented by Salt Lake City policeman, Lester F Wire in 1912. Wire’s traffic signal was hand-made, using a yellow wooden box resembling a bird house. The signal was installed at the intersection of Main Street and 200 South in Salt Lake City. Inspired by naval and railroad signals, Wire installed lights dipped in red and green paint inside two six-inch circular openings on each side to control traffic. The signal, mounted on a 10ft pole, was manually operated by a policeman using a two-way throw switch below.

UDOT says it has a rich history of innovative traffic solutions from 1912 to the present day. In 1917, the first interconnected traffic signal system in the world was installed in Salt Lake City, with six connected intersections controlled simultaneously from a manual switch. In 2007, UDOT installed one of the USA’s first continuous flow interchanges (CFIs) at Bangerter Highway and 3500 South. There are currently 10 CFIs in use in the state. The agency is also well known for its innovative bridge construction. Using Accelerated Bridge Construction, a process that reduces delays from months to days, UDOT has moved more bridges than the rest of the USA combined.

“From a converted bird house on Main Street in Salt Lake City, the traffic signal can now be found throughout the world; even in the most remote locations,” UDOT executive director, John Njord, said. “Lester Wire was the first of many Utahns inventing innovative traffic solutions. We are committed to fostering an environment of innovation that will ensure UDOT remains a worldwide leader in innovative road construction.”

5 October 2012